From: Nicolas Schier <n.schier@xxxxxx>
Remove holders recursively when removal of module holders is requested.
Extend commit 42b32d30c38e ("modprobe: Fix holders removal") by removing
also indirect holders if --remove-holders is set. For a simple module
dependency chain like
module3 depends on module2
module2 depends on module1
'modprobe -r --remove-holders module1' will remove module3, module2 and
module1 in correct order:
$ modprobe -r --remove-holders module1 --verbose
rmmod module3
rmmod module2
rmmod module1
(Actually, it will do the same when specifying module2 or module3 for
removal instead of module1.)
As a side-effect, 'modprobe -r module3' (w/o --remove-holders) will also
remove all three modules, as after removal of module3, module2 does not
have any holders and the same holds for module1 after removal of
module2:
$ modprobe -r module3 --verbose
rmmod module3
rmmod module2
rmmod module1
Without recursive evaluation of holders, modprobe leaves module1 loaded.
Unfortunately, '--dry-run --remove-holders' breaks with indirect
dependencies.
Signed-off-by: Nicolas Schier <n.schier@xxxxxx>
---
While commit 42b32d30c38e ("modprobe: Fix holders removal", 2022-03-29) already
implements removing first-level holders, indirect holders were not evaluated.
In a simple module dependency chain like
module3 depends on module2
module2 depends on module1
'modprobe -r --remove-holders module1' was only considering module2 and module1
and thus had to fail as module3 was still loaded and blocking removal of
module2.
By doing recursive depth-first removal this can be fixed for such simple
dependency.
---
To: linux-modules@xxxxxxxxxxxxxxx
Cc: Lucas De Marchi <lucas.de.marchi@xxxxxxxxx>
---
I am a bit unhappy about the introduction of the 'recursive' parameter
to rmmod_do_modlist() as it always holds the same value as
stop_on_errors; is re-using (and renaming) possibly a better option?
---
tools/modprobe.c | 37 ++++++++++++++++++++++++++++---------
1 file changed, 28 insertions(+), 9 deletions(-)
diff --git a/tools/modprobe.c b/tools/modprobe.c
index 3b7897c..9cbb236 100644
--- a/tools/modprobe.c
+++ b/tools/modprobe.c
@@ -390,13 +390,25 @@ static int rmmod_do_remove_module(struct kmod_module *mod)
static int rmmod_do_module(struct kmod_module *mod, int flags);
/* Remove modules in reverse order */
-static int rmmod_do_modlist(struct kmod_list *list, bool stop_on_errors)
+static int rmmod_do_modlist(struct kmod_list *list, bool stop_on_errors,
+ bool recursive)
{
struct kmod_list *l;
kmod_list_foreach_reverse(l, list) {
struct kmod_module *m = kmod_module_get_module(l);
- int r = rmmod_do_module(m, RMMOD_FLAG_IGNORE_BUILTIN);
+ int r = 0;
+
+ if (recursive) {
+ struct kmod_list *holders = kmod_module_get_holders(m);
+
+ r = rmmod_do_modlist(holders, stop_on_errors,
+ recursive);
+ }
+
+ if (!r)
+ r = rmmod_do_module(m, RMMOD_FLAG_IGNORE_BUILTIN);
+
kmod_module_unref(m);
if (r < 0 && stop_on_errors)
@@ -448,13 +460,13 @@ static int rmmod_do_module(struct kmod_module *mod, int flags)
}
/* 1. @mod's post-softdeps in reverse order */
- rmmod_do_modlist(post, false);
+ rmmod_do_modlist(post, false, false);
/* 2. Other modules holding @mod */
if (flags & RMMOD_FLAG_REMOVE_HOLDERS) {
struct kmod_list *holders = kmod_module_get_holders(mod);
- err = rmmod_do_modlist(holders, true);
+ err = rmmod_do_modlist(holders, true, true);
if (err < 0)
goto error;
}
@@ -472,9 +484,16 @@ static int rmmod_do_module(struct kmod_module *mod, int flags)
}
}
- if (!cmd)
- err = rmmod_do_remove_module(mod);
- else
+ if (!cmd) {
+ int state = kmod_module_get_initstate(mod);
+
+ if (state < 0) {
+ /* Module was removed during recursive holder removal */
+ err = 0;
+ } else {
+ err = rmmod_do_remove_module(mod);
+ }
+ } else
err = command_do(mod, "remove", cmd, NULL);
if (err < 0)
@@ -488,14 +507,14 @@ static int rmmod_do_module(struct kmod_module *mod, int flags)
kmod_list_foreach(itr, deps) {
struct kmod_module *dep = kmod_module_get_module(itr);
if (kmod_module_get_refcnt(dep) == 0)
- rmmod_do_remove_module(dep);
+ rmmod_do_module(dep, flags);
kmod_module_unref(dep);
}
kmod_module_unref_list(deps);
}
/* 5. @mod's pre-softdeps in reverse order: errors are non-fatal */
- rmmod_do_modlist(pre, false);
+ rmmod_do_modlist(pre, false, false);
error:
kmod_module_unref_list(pre);
---
base-commit: 3d1bd339ab942ea47e60f053f4b11b0c47ff082b
change-id: 20230309-remove-holders-recursively-f667f32e2a7d
Best regards,
--
Nicolas Schier
